1. Field of the Invention
The present invention relates to a securing structure for a solar cell module for installing the solar cell module on roof.
2. Description of the Related Art
Various securing structures for installing a solar cell module on roof have been proposed (see, Japanese Patent Application Laid-open Nos. 2006-037545 and 2006-144266). In the securing structures, a plurality of long vertical crosspieces are secured onto a roof material such as roof tiles and slate so as to extend in the roof inclination direction (also referred to as flow direction) at an interval in the roof lateral direction. Then, a plurality of long lateral crosspieces are secured onto these vertical crosspieces so as to extend in the roof lateral direction at an interval corresponding to the length of the short sides of the solar cell module. In such a manner, a mounting mount in a form of parallel crosses is formed. Then, the long sides of the solar cell module are placed and secured onto the lateral crosspieces of the mounting mount.
In the securing structures as described in Japanese Patent Application Laid-open Nos. 2006-037545 and 2006-144266, the mounting mount is formed in the form of parallel crosses. This requires a large number of crosspiece members and increases the number of parts, resulting in a problem that the cost for installing the solar cell module is increased.
For solving this problem, the present applicant has proposed the following securing structure (see, Japanese Patent Application Laid-open No. 2010-261257). In the securing structure, a plurality of long crosspiece members are secured in parallel onto a roof material and fastening members are supported on the crosspiece members so as to slide in the extending direction thereof. Further, a solar cell module is placed on the plurality of crosspiece members such that a pair of opposing sides of the solar cell module intersect with the crosspiece members. Then, the solar cell module is pressed to the crosspiece members to be secured by securing members through the fastening members supported on the crosspiece members.
With this structure, the solar cell module is directly secured onto the long crosspiece members secured onto the roof material. This eliminates necessity for arranging the crosspiece members in the form of parallel crosses to configure the mounting mount. Therefore, the number of parts for installing the solar cell module can be reduced, thereby reducing the cost.
Meanwhile, in Japanese Patent Application Laid-open Nos. 2006-037545, 2006-144266, and 2010-261257, in order to achieve a state where the upper surfaces of a plurality of solar cell modules are aligned in the same plane, when the plurality of long crosspiece members (vertical crosspieces) are secured in parallel onto the roof material, they are secured such that the upper surfaces of the respective crosspiece members are aligned in the same plane parallel with the surface of roof. That is to say, the plurality of long crosspiece members are secured while making adjustment of aligning the upper surfaces of the plurality of crosspiece members to the same height from the surface of the roof. There is, however, a problem that the adjustment of the heights of the plurality of crosspiece members requires mature techniques and troublesome tasks. Further, when the adjustment is insufficient, the upper surfaces of the plurality of solar cell modules placed on the crosspiece members are not in the same plane and are in an uneven state. This arises a problem that appearance is unattractive and there is a risk that the solar cell modules bend and are broken when the solar cell modules are secured onto the crosspiece members. The adjustment of the heights referred herein also includes adjustment of aligning the upper surfaces of the plurality of solar cell modules to be in the same plane and adjustment of parallelism between the upper surfaces of the solar cell modules and a specific surface (for example, the surface of the roof or an optimum arrangement surface based on latitude of an installing place).
On the other hand, when the plurality of solar cell modules are installed on the roof, the solar cell modules are required to be grounded. When the respective solar cell modules are grounded separately, grounding conductors by the number of solar cell modules are required to extend to the ground from the roof. This arises problems that wiring becomes cumbersome and troublesome tasks are needed. For avoiding the problems, grounding terminals are screwed on frame bodies of the respective solar cell modules, which are made of metal, and the terminals are connected through a wire cable so as to connect the respective solar cell modules to each other. Then, the grounding conductor is made to extend from one solar cell module to the ground, a construction made of metal, or the like.
In this case, holes are opened on the frame bodies of the solar cell modules for screwing. This arises a risk that devices in the solar cell modules are damaged depending on screwing positions. In addition, hole parts are exposed to wind and rain because the holes are opened on the frame bodies of the solar cell modules. Therefore, there is a risk that the frame bodies with the hole parts become easy to be corroded and durability of the solar cell modules is lowered due to the corrosion of the frame bodies.
In order to solve this, Japanese Patent Application Laid-open No. 2006-144266 has proposed the following technique. That is, protrusions sticking in the upper surfaces of the frame bodies of the solar cell modules are provided on a pressing member made of metal, which presses down the pair of solar cell modules placed on the lateral crosspieces from above simultaneously to secure them. This causes the solar cell modules to be connected electrically each other through the pressing member. However, in the technique in Japanese Patent Application Laid-open No. 2006-144266, rainwater is easy to be accumulated on portions in which the protrusions stick because the protrusions for grounding are made to stick therein from above the solar cell modules. When electric current flows between the protrusions and the solar cell modules (frame bodies) in a state where water is accumulated on the portions in which the protrusions stick, there arises the following risk. That is, electric corrosion is generated on the portions and durability of the solar cell modules is lowered due to the corrosion of the frame bodies.